BDE : Prevent "Index Out Of Date" & "Blob has been modified" errors and loss of data

Hi there

If you are using the BDE you may have experienced these problems, 'Index Out Of Date' or 'Blob has been modified' errors and data loss upon a bad reboot or an application crash.

There are a two ways to fix these problems each method will force the BDE to flush the cache after every post/delete and will simultaneously fix those problems.

1)Set the Local Share setting in the BDE Adminstrator to true (goto Configuration->System->Init->Local Share). Doing this will create Paradox.lck and Pdoxusrs.lck files in the the folders where the tables recide, they will only be automatically delete if you exit the application properly. So on startup of the application before opening the tables make sure to check the existence and delete those files, if you do not delete those files you might them get another notorious error "Directory is controlled by another .NET file".

//Lets say the tables recide in the DB folder
if(FileExists("c:\\db\\Paradox.lck"))
DeleteFile("c:\\db\\Paradox.lck");

if(FileExists("c:\\db\\Pdoxusrs.lck"))
DeleteFile("c:\\db\\Pdoxusrs.lck");

//Open the Tables
Table1->Active=true;
....

2) Call DBISaveChanges(Table's->Handle) on the AfterPost and AfterDelete events of the Table's.

You can assign the same procedure to all the AfterPost and AfterDelete events of the all the Tables on your form


//---------------------------------------------------------------------------
void __fastcall TForm1::TableAfterPost(TDataSet *DataSet)
{
DbiSaveChanges((dynamic_cast <TTable *> (DataSet))->Handle);
}
//---------------------------------------------------------------------------

If you follow either of the options mentioned you should not have those problems but there is still a chance that the table may become corrupt and you can get a 'Index Out Of Date Error' and other various errors, though it is very rare, so I recommend a utility called PdxrBld which is based on Borland's Tutil32.dll

PdxrBld(open source)
http://www.rksolution.cz/Delphi/Delphi.htm#00004

TUtil32.Dll and Borlands own open source utility
http://info.borland.com/devsupport/bde/utilities.html

Also these articles are a must read,

"Lock file has grown too large"
http://community.borland.com/article/0,1410,15256,00.html

"Some current internal limits of BDE"
http://community.borland.com/article/0,1410,15159,00.html

"Table is Full with Paradox Tables"
http://community.borland.com/article/0,1410,10318,00.html

"BDE setup for Peer-To-Peer(Non-Dedicated) Networks"
http://community.borland.com/article/0,1410,15247,00.html

Hope this helps someone